646922761 has 2 divisors, whose sum is σ = 646922762. Its totient is φ = 646922760.

The previous prime is 646922741. The next prime is 646922797. The reversal of 646922761 is 167229646.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 610090000 + 36832761 = 24700^2 + 6069^2 .

It is a cyclic number.

It is not a de Polignac number, because 646922761 - 2⁵ = 646922729 is a prime.

It is not a weakly prime, because it can be changed into another prime (646922741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323461380 + 323461381.

It is an arithmetic number, because the mean of its divisors is an integer number (323461381).

Almost surely, 2^646922761 is an apocalyptic number.

It is an amenable number.

646922761 is a deficient number, since it is larger than the sum of its proper divisors (1).

646922761 is an equidigital number, since it uses as much as digits as its factorization.

646922761 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 43.

The square root of 646922761 is about 25434.6763494250. The cubic root of 646922761 is about 864.8699553907.

The spelling of 646922761 in words is "six hundred forty-six million, nine hundred twenty-two thousand, seven hundred sixty-one".